In the art of charging a refrigeration or air conditioning system, it is common for the system to have a process fitting which encloses a valve. Preferably, the fitting is adapted to receive a quick connect and disconnect coupling such as disclosed, for example, in U.S. Pat. No. 4,889,149 which issued to the Assignee of the present invention. This patent discloses an automatic air actuated dispensing tool assembly which grips or locks onto the process fitting, evacuates the refrigeration or air conditioning system and then charges the system with a predetermined volume of refrigerant. The valves are then automatically closed, and the assembly is automatically released from the process fitting. This dispensing tool assembly is ideally suited for use in automotive or motor vehicle assembly plants or in refrigeration and air conditioning assembly plants.
In plants which are less automated or in the after market, it is common to use a manually operated quick connect and disconnect coupling for attaching a flexible hose to the process fitting on the system, after which the system is evacuated and/or charged with refrigerant supplied through the hose. According to one type of quick connect and disconnect coupling, a manually retractable spring biased sleeve or collar surrounds a set of balls confined within corresponding holes, and the balls are adapted to project into a reduced neck portion of the process fitting to lock the coupler onto the fitting.
The coupler may also enclose a valve opening member which opens the fitting valve when the coupling is inserted axially onto the fitting. When the coupler is manually disconnected from the fitting, a small amount of the gas refrigerant normally escapes into the atmosphere either from the fitting and/or from the supply hose. Since the gas refrigerant may pollute the atmosphere, it is desirable to eliminate or minimize the volume of refrigerant that escapes during the connecting and disconnecting operations, as stated in above-mentioned U.S. Pat. No. 4,889,149.